The Upper Jurassic - Lowermost Cretaceous Source Rocks in the Central Graben, North Sea - Status and Future Challenges

Abstract

The principal source rocks in the Danish and southern Norwegian Central Graben in the North Sea are the Upper Jurassic to lowermost Cretaceous marine shales of the Farsund Formation that corresponds to the Kimmeridge Clay Formation and equivalents elsewhere in the North Sea. The evaluation of the Farsund Formation shales shows that the distribution of the generation potential and the maturity is more complex than generally accepted. Further studies are required to understand the variations in source rock quality, the controlling factor(s) on kerogen composition, and to determine if the rich intervals can be regionally correlated. The Upper Jurassic marine shales underlying (Lola and Haugesund Formations) the Farsund Formation are traditionally not included as potential source rocks, but the documented extra potential of the Upper Jurassic shales below the Farsund Formation should be investigated in more detail. Attention should also be given to deeply buried mature source rocks in areas with overpressure. These factors have considerable impact on location and extent of kitchen areas. The problems are explored with the goal to capture new knowledge of the Upper Jurassic petroleum source rocks.